|P is for Practical
Cool. I hadn't seen Text::Quote, much less realized from its unassuming name that it did compression. I'm curious -- what problem or itch inspired you?
As for using the self-extracting code as a fallback, the algorithms requiring Huffman coding (bzip and Huffman) are probably not a good choice, since they require a priority queue module, which you're less likely to have than Compress::Zlib. I've only done "compressed", stand-alone versions of the decompression routines. Indeed, I hadn't thought about it as a zlib alternative on the compression end of things.
The idea is that while I may have a bunch of strange modules on my system, the system where my script is running may just have the bare bones. This way I can compress the script, then use it elsewhere without adding any new module dependencies (like those Stuffit self-extracting archives that were so popular before all compression software was free). So if you changed T::Q to use this, you'd probably want to give the user the option of using it even if they happen to have Compress::Zlib on the system where T::Q is running.